Change the ISPConfig SSL

Hi, I need change the Common Name (CN) in the SSL Certificate of ISPConfig because when i enter in the ispconfig panel or in the webmail always i have a warning that not are equal the CN and the domain.
¿How can i make this change?
I have a ISPConfig 2.2.27 on Debian Etch, in production.
Thanks

Well, only i need that not shown warning at all times.
If I change the CN then only will I see the warning the first time that i enter in the domain. Now I see the warning every time I enter the domain.
If I make my own ssl, what I have to replace file? And after i only need restart ispconfig?
Thanks